In the microelectronics industry, before integrated circuit (IC) chips are packaged in an electronic component, such as a computer, they are tested. Testing is essential to determine whether the integrated circuit's electrical characteristics conform to the specifications to which they were designed to ensure that electronic component performs the function for which it was designed.
Testing is an expensive part of the fabrication process of contemporary computing systems. The functionality of every I/O for contemporary integrated circuit must be tested since a failure to achieve the design specification at a single I/O can render an integrated circuit unusable for a specific application. The testing is commonly done both at room temperature and at elevated temperatures to test functionality and at elevated temperatures with forced voltages and currents to burn the chips in and to test the reliability of the integrated circuit to screen out early failures.
Contemporary probes for integrated circuits are expensive to fabricate and are easily damaged. Contemporary test probes are typically fabricated on a support substrate from groups of elongated metal conductors which fan inwardly towards a central location where each conductor has an end which corresponds to a contact location on the integrated circuit chip to be tested.
The metal conductors generally cantilever over an aperture in the support substrate. The wires are generally fragile and easily damage and are easily displaceable from the predetermined positions corresponding to the design positions of the contact locations on the integrated circuit being tested. These probes last only a certain number of testing operations, after which they must be replaced by an expensive replacement or reworked to recondition the probes.
FIG. 1 shows a side cross-sectional view of a prior art probe assembly 2 for probing integrated circuit chip 4 which is disposed on surface 6 of support member 8 for integrated circuit chip 4. Probe assembly 2 consists of a dielectric substrate 10 having a central aperture 12 therethrough. On surface 14 of substrate 10 there are disposed a plurality of electrically conducting beams which extend towards edge 18 of aperture 12. Conductors 16 have ends 20 which bend downwardly in a direction generally perpendicular to the plane of surface 14 of substrate 10. Tips 22 of downwardly projecting electrically conducting ends 20 are disposed in electrical contact with contact locations 24 on surface 25 of integrated circuit chip 4. Coaxial cables 26 bring electrical signals, power and ground through electrical connectors 28 at periphery 30 of substrate 10. Structure 2 of FIG. 1 has the disadvantage of being expensive to fabricate and of having fragile inner ends 20 of electrical conductors 16. Ends 20 are easily damaged through use in probing electronic devices. Since the probe 2 is expensive to fabricate, replacement adds a substantial cost to the testing of integrated circuit devices. Conductors 16 were generally made of a high strength metal such as tungsten to resist damage from use. Tungsten has an undesirably high resistivity.